Compounds of the general formula: ##STR2## where R.sub.5 ' is the group --(CH.sub.2).sub.n --OH and n is 2, 3, 4, or 6 are known. These compounds have an antitumor activity but at the same time are very toxic (see Hirano, Tetrahedron Letters No. 10 (1979) pages 883-886; Peter, Cancer Chemother. Pharmacol. 3 (1979) pages 181-188).
Furthermore, in Draeger, Cancer Treatment Reports 60 (1976) pages 355-359, there is described the formation of compounds of the formula: ##STR3## where R.sub.5 " is the group --CH.sub.2 --CH--(NH.sub.2)--COOH or --CH.sub.2 CH(NHCOCH.sub.3) --COOH from 4-hydroxy-cycliphosphamide and cysteine, N-acetyl cysteine or glutathione.
The entire disclosures of the Hirano, Peter, and Draeger articles are hereby incorporated by reference and relied upon.